llEmail() Randomly and Silently Failing

I had an off-world email forwarder for a while. That was my protection against the server UUID changing - the scripts only needed to know the off-world address, and all I had to do was update the forwarder if my server was re-rezzed.

It worked for that purpose (allowing a server re-rez), but it was still pretty unreliable. I never tried direct email to another object, so I don't know if going out and back into SL was better than staying in SL, maybe it was.

HTTP has just been more steady for me. Sure, you go through hiccups while you're getting it working, and bugs in your PHP script(s) can result in nothing coming back. But once you've got that stuff sorted out, I've never had a case where a message just randomly did not show up for no reason. I used to get that fairly frequently with email and XML-RPC.

If you login to the JIRA (rather than browsing it without logging in), there are links to find issues you have reported and voted on.

yes, they did, and probably still do in some form. However I remember there was a period where they were having high failure rates and outages, and I'm pretty sure part of their improvements was to migrate many things to HTTP. SLX/Onrez are both pretty reliable now.